EMF 35 JMIP study: preliminary results and implications for Japan’s climate change mitigation

The present study, Stanford Energy Modeling Forum (EMF) 35 Japan Model Intercomparison project (JMIP), employs five energy-economic and integrated assessment models to evaluate long-term climate change mitigation of Japan. Japan submitted its mid-century strategy last June to the Framework Convention on Climate Change, but the submitted strategy has not yet gone through modeling analysis. Moreover, along with other countries, Japan is expected to update its policy pledges in 2020. This study contributes modeling analysis to the ongoing policy debate. A preliminary analysis has been reported by Sugiyama et al. (2019, https://doi.org/10.1016/j.energy.2018.10.091) and this study further extends it. EMF 35 JMIP conducts a suite of sensitivity analysis on dimensions including emissions constraints, technology availability, and demand projections. The five participating models are: AIM/CGE, AIM/Enduse, DNE21, IEEJ, and TIMES-Japan. Four are bottom-up models, and one (AIM/CGE) is a computable general equilibrium model. We have harmonized GDP and population assumptions across models. The overall results confirm that mitigation strategies that work in other jurisdictions are also applicable in Japan, including energy efficiency, electricity decarbonization, and electrification. We also find that absent structural changes in the economy, heavy industry will be one of the hardest to decarbonize. Partly because of the challenges associated with industrial decarbonization, the marginal cost of abatement is higher than in the United States and comparable to that of Europe, as indicated by previous exercises of the EMF project. The challenge of industrial mitigation can be found in other Asian countries, particularly China and South Korea, and further investigation is warranted.